In Deuteronomy Rabba Ki Teze section 2, (ed. S. Liebermann, p. 103) we read the following passage: ‘R. Abba b. Kahana said: …. It is like unto a king who hired for himself workers and put them into his orchard, without revealing to them the wages for looking after the orchard, so that they should not pay no attention to that for which they would be paid little and concern themselves only with that for which they would be paid much. In the evening he called for each of them. He said to the first, “Under which tree did you work ?” The worker replied, “Under the pepper-tree.” “The rate for this one is one gold piece (= aureus),” [said the King]. He called to the second and asked him, “Beneath which tree did you work ?” “Under that one,” he replied. He (the King) said, “This is a perach-lavan tree [literally, a white-flower tree], and the rate for it is half a gold piece.” He called the last one and said to him, “Under which tree did you work ?” “Under this one,” he answered. “It is an olive-tree, and its rate is two hundred mana.”’
Since in this parable we begin with one gold piece and then go down to half a gold piece it would appear likely that the final sum mentioned is a quarter of a gold piece. If this albeit hypothetical supposition be accepted then it follows that ¼ aureus = 200 mana, ∴ 1 aureus = 800 mana.